DCC no go backwards on DC

[dragenrider]

My friend just bought two brand new engines with a decoder already installed in each. He doesn't operate a DCC layout yet, just regular cab control. The problem is that both engines run fine forward but won't respond in reverse UNLESS the direction switch is quickly bumped back and forth. Then they take off like scalded apes. [banghead]

Any ideas? Switching the direction the engine is facing doesn't help. [|(]

[AggroJones]

Are they Atlas or BLI?

[dragenrider]

Neither. They are by Intermountain.

I checked and found that they were advertised to run on regular DC system.

[Eriediamond]

Looks like you've not had many responses here. First be advised I'm not a DCC person, but from what I do know is that locomotives come as straight DC, or DCC ready which means you just have to plug a decoder into the board and program it. Now, if those locos came with the decoder already installed, the decoder will have to be unplugged and the DC jumper replaced is my guess here. Was there any instructions that came with those engines? Hopefully this will help some.

[cacole]

Unless the decoders have been specifically programmed to run on both an analog (DC) and DCC layout, they will not run on straight DC and should not be placed on a track that is powered with DC. Depending on the type of decoder that is in them, trying to run them on DC could cause the decoders to burn up.

P.S. --
I just checked Intermountain's Web stie. If those locomotives are the N-scale SD40-2, they are NOT DCC equipped -- just DCC READY. The big difference here is that there is NO DECODER in them, they just have a socket so a decoder can be plugged in if you want to use DCC.

The erratic running symptoms you describe indicate a bad power pack. Never try to use a cheap toy train transformer out of a Tyco, Bachmann, or similar Christmas train set -- if you can afford Intermountain locomotives then you need to invest in a good power supply before you ruin good locomotives.

[Anonymous]

Sounds like the reverse switch in your power pack is the likely cause. I would test it with a meter or a light bulb before blaming the new locomotives.

[dragenrider]

I'll try testing the direction switch with other engines.

The decoder is direct wired to the motor without the 8-pin plug. These are HO scale, by the way.

[Anonymous]

DCC decoders have a particular CV that needs to be set to allow them to run under DC, that much I do know. I too would suggest checking the power pack is ok. One potential test would be to hook a 9v (PP3, used in domestic smoke alarms over here) battery up to the rails one way, then change the polarity. If the loco runs properly in both directions (note that it will move quickly, so be careful!) the problem is likely to be the power pack. Learned this at my LHS - they use a 9v battery to quickly check if secondhand locos they are buying in work.

[Anonymous]

Who makes the Decoders?

[cacole]

Information on Intermountain's Web site indicates that they do not make locomotives with decoders pre-installed, but only DCC ready. If these locomotives have had the decoders hard wired, that means they are older models that did not have a DCC socket. Whoever installed the decoders may have wired them wrong. Find out what brand of decoder in in these models, download the operating manual from the decoder manufacturer, and check the wiring to see if they were properly installed.

[darth9x9]

Along with the proper programming of the decoder to allow it to respond to DCC and DC signals as mentioned above, another thing to look at it the DC power supply. If it uses pulsed DC, DCC equipped locos will not operate properly on it. I have seen this first hand on a friend's layout. The loco would operate normally in one direction and not at all or at high speeds in another. I ended up running my three units (Atlas GP40s) elephant style so that all three decoders were "forward" when it saw the pulsed DC signal. They ran in one direction around the layout all that evening.

[Eriediamond]

Hmmmm, problem-problems, me thinks me go back to wind-up trains. On second thoght I guess not, I'd probabley loose the key!! [(-D][(-D][(-D][(-D]

[darth9x9]

QUOTE: Originally posted by Eriediamond

Hmmmm, problem-problems, me thinks me go back to wind-up trains. On second thoght I guess not, I'd probabley loose the key!! [(-D][(-D][(-D][(-D]

[(-D][(-D][(-D]Hee, hee, hee, hee, hee, hee. [(-D][(-D][(-D]

I don't see it as problems so much,,, just making better choices with knowledge and experience learned by others. After all, this hobby is about sharing.[tup]